Filter circuit, filter, and electronic device

Abstract

A filter circuit, a filter, and an electronic device are disclosed. The filter circuit includes: a first port and a second port arranged opposite to each other, a grounding terminal, a series branch between the first port and the second port, and at least one parallel branch connected with the series branch; where the series branch includes at least one series resonance unit arranged in sequence, each of the at least one parallel branch includes a parallel resonance unit, and the parallel resonance unit is connected with the grounding terminal.

1 . A filter circuit, comprising:
 a first port and a second port arranged opposite to each other, a grounding terminal, a series branch between the first port and the second port, and at least one parallel branch connected with the series branch;   wherein the series branch comprises at least one series resonance unit arranged in sequence, each of the at least one parallel branch comprises a parallel resonance unit, and the parallel resonance unit is connected with the grounding terminal.   
     
     
         2 . The filter circuit according to  claim 1 , wherein each series resonance unit and each parallel resonance unit both comprise an input terminal and an output terminal arranged opposite to each other, a first capacitor, a second capacitor and an inductor;
 a first electrode of the first capacitor and a first electrode of the second capacitor are both connected with the input terminal, and a second electrode of the first capacitor is connected with a first electrode of the inductor;   a second electrode of the second capacitor and a second electrode of the inductor are both connected with the output terminal.   
     
     
         3 . The filter circuit according to  claim 2 , wherein the filter circuit comprises one series resonant unit, an input terminal of the series resonance unit is connected with the first port, an output terminal of the series resonance unit is connected with an input terminal of each parallel resonance unit and is connected with the second port, and an output terminal of each parallel resonance unit is connected with the grounding terminal. 
     
     
         4 . The filter circuit according to  claim 2 , wherein the at least one series resonant unit comprises a first series resonant unit and a second series resonant unit sequentially arranged between the first port and the second port, an input terminal of the first series resonance unit is connected with the first port, an output terminal of the first series resonance unit is connected with an input terminal of the second series resonance unit, an input terminal of each parallel resonance unit is respectively connected with the output terminal of the first series resonance unit and the input terminal of the second series resonant unit, and an output terminal of each parallel resonance unit is connected with the grounding terminal. 
     
     
         5 . The filter circuit according to  claim 4 , wherein the series branch further comprises a third capacitor, a first electrode of the third capacitor is connected with the output terminal of the first series resonance unit, and a second electrode of the third capacitor is connected with the input terminal of each parallel resonance unit. 
     
     
         6 . The filter circuit according to  claim 5 , wherein the series branch further comprises a fourth capacitor, a first electrode of the fourth capacitor is connected with the input terminal of the second series resonant unit, and a second electrode of the fourth capacitor is connected with the input terminal of each parallel resonance unit. 
     
     
         7 . The filter circuit according to  claim 2 , wherein the filter circuit comprises a plurality of parallel resonance units, the series branch further comprises at least one fifth capacitance, a first electrode and a second electrode of each of the at least one fifth capacitor are respectively connected with input terminals of two adjacent parallel resonance units. 
     
     
         8 . The filter circuit according to  claim 1 , wherein a connecting line between a capacitor and an inductor in the filter circuit is a thick and short connecting line. 
     
     
         9 . The filter circuit according to  claim 8 , wherein a quantity of the at least one series resonance unit is equal to a quantity of transmission zero points generated by the filter circuit at high frequency out-of-band suppression. 
     
     
         10 . The filter circuit according to  claim 9 , wherein a quantity of at least one parallel resonance unit is equal to a quantity of the transmission zero points generated by the filter circuit at low frequency out-of-band suppression. 
     
     
         11 . A filter, comprising: the filter circuit according to  claim 1 . 
     
     
         12 . The filter according to  claim 11 , wherein each series resonance unit and each parallel resonance unit in the filter both comprise an input terminal and an output terminal arranged opposite to each other, a first capacitor, a second capacitor and an inductor; a first electrode of the first capacitor and a first electrode of the second capacitor are both connected with the input terminal, and a second electrode of the first capacitor is connected with a first electrode of the inductor; a second electrode of the second capacitor and a second electrode of the inductor are both connected with the output terminal; the inductor comprises a base substrate, a metallized through hole penetrating through the base substrate, and re-distribution layer wirings respectively arranged on opposite sides of the base substrate. 
     
     
         13 . The filter according to  claim 12 , wherein a substrate of the filter is a glass substrate. 
     
     
         14 . The filter according to  claim 11 , wherein the filter is a band-pass filter. 
     
     
         15 . An electronic device, comprising: the filter according to  claim 11 .